Just an update for those who are following this thread. I've recently crossed 14K km (8,700 miles) and put the last couple of months of receipts into my spreadsheet today and the results are as follows: lifetime average (calculated) is 10L/100km (23.5 mpUSg) and average for the dash display is 9.4L/100km (25 mpUSg). I'm pretty happy with that, since the calculated mpg is just UNDER what my 2010 Sonata (2.4 with stick) was doing, and life is a lot more fun in the Mustang!

I have found with my 2012 F150 EcoBoost I have my choice between Eco or Boost but not both. Same on my wife's 4 banger EcoBoost Lincoln.

Another thing I have learned about cruise control: if you have a heavy foot and a touch of aggression (Who? ME?), using cruise control to stay at an economical pace can save gas. Keeps me from trying to keep up with faster traffic and dodging for those openings in traffic.

HOWEVER, if you use self control and maintain an economical pace, you will get better mileage by regulating the speed yourself. Going down hill? Allow it to pick up a little speed and use that excess getting up the next hill. Instead of giving it the gas going up the hill, try and maintain even gas peddle pressure, keep that turbo from spinning up. Cruise Control is constantly giving it gas and letting off to maintain steady pace, working against gravity and momentum instead of utilizing it.

I rarely get the mileage figures claimed for my EcoBoost but I have taken a few occasions to really try and have gotten some pretty good numbers. My wife drives me crazy, on the gas, off the gas, on the gas, off the gas. I can get a couple more MPG on her car than she does.

My brother has a 2018 Mustang EcoBoost that he commutes over a 100 miles per day, he says he often sees 30-31+ mpg but routinely gets 28+ miles per gallon (he currently has 15,000 miles on his car). As for me, I have now had my 2017 EcoBoost for 9 months, have put about 22K miles on it and I routinely get 23-25 mpg, with an occasional 26-28 mpg.

Picked up my '19 Ecoboost in December... just hit 28,000km in it. This car is my daily driver so I have a mix of city and highway but my daily commute is only 12km each way. All the rest of that distance has been for fun.
Overall, I'm getting 8.3l/100km (28mpg).
Did a 4,800km road trip with my wife last week: Montreal to PEI to Halifax to Boston to NYC and back to Kitchener. Did a little better with a higher percentage of city driving at 8.0l/100km (29mpg).

Of an interesting note, I've been playing around with different octane fuel, running at least four tanks before switching.
I haven't found any appreciable fuel economy difference between 87 and 94 octane but the car is a lot more fun to drive when running 94.

We have had the 2018 EcoBoost almost a month. I averaged 31 mpg when the grandkids were with us and the wife hauled them around in the F150 SCrew. I drive 13 miles one way to work on a tollway at 75 to 80, she drives about 5 miles farther on the same road and gets 28.8 to 29 mpg.. So she must be hammering the pedal getting to the toll road.

Ford's mileage calculators are a little screwy if you don't reset the trip odometer. My dad's Focus claimed it was getting something near 60 mpg @80mph, when I drove it out to California, through Utah, and back to Kansas. I didn't reset it for about 3000+ miles, and on the last part of the trip, that little mileage counter got pretty optimistic. I could see my mileage numbers going up sometimes by 1 mpg at a time as I came down into Kansas from Colorado. Good thing it wasn't accurate - I'd have had to stop and drain off some gasoline just to get home!